Activity 1.2 — detectives don't just collect evidence. They run experiments to make more of it.
4 days · You will design and run a real experiment on a real human being
(your partner) — and try to lower a vital sign on purpose.
Tap any glowing word for the meaning in English and Spanish.
A company says its new medicine treats a disease. A coach says an energy drink makes athletes faster. Your friend says chewing gum helps you focus.
How would you actually find out if any of that is true? Doctors, researchers, and scientists face this question every day — and their answer is to run an experiment and let the data decide.
Think about it: what would you measure, and what would you compare it to? Keep that question in your pocket — it is the whole activity.
Scientists plan experiments with a step-by-step process, so the work is clear, logical, and repeatable — another scientist could run it the exact same way and check the results.
State a specific, testable question.
"Does 2 minutes of jumping jacks increase respiratory rate?"
Write a hypothesis — a prediction built on what you already know, not just a hunch.
Pick variables, list materials, note safety, include a control, write numbered steps, plan the data table, use multiple trials.
Carry it out, record data and observations, look for patterns, then say whether the results support the hypothesis.
Not a strict recipe: real scientists loop back — they change a hypothesis, redesign a flawed procedure, or ask a brand-new question. Going backward is not failing; it is doing science.
A scientist varies the amount of fertilizer in each pot, then measures the height of each plant after one week and two weeks.
So the experiment can be replicated — repeated in exactly the same way by anyone, anywhere. If nobody can repeat your work, nobody can trust your conclusion.
The thing you change on purpose.
Jumping-jacks experiment: doing jumping jacks for two minutes.
Bean plants: the amount of fertilizer.
The thing you measure — it depends on what you changed.
Jumping jacks: respiratory rate.
Bean plants: the height of the plant.
Memory hook: I change the Independent variable. The Dependent variable Depends on it — that is the one you measure. And test one variable at a time: jumping jacks plus loud music means you cannot tell which one moved the number.
In Activity 1.1 you saw what pushes vital signs up: exercise, stress, excitement. But how much control do you have the other way?
Can you make your heart rate or breathing rate go down — on purpose? That is a real, testable question. Today your team designs the experiment that answers it.
Doctors care about this for real: teaching patients to calm their own heart rate is part of treating pain, anxiety, and even heart disease.
Heart rate (beats per minute)
or
Respiratory rate
(breaths per minute)
This becomes your dependent variable.
Slow deep breathing · calm music · eyes closed and still · a gentle stretch · picturing a
calm place — or your own idea (cleared by your teacher).
This becomes your
independent variable.
One variable at a time: deep breathing with calm music is two experiments mashed together. Pick one thing and test it honestly.
Write both on Worksheet 3 — Design. A hypothesis is not a guess — back it with a reason: "because slow breathing signals the body to calm down."
Your relaxation technique — the thing you change.
Your chosen vital sign — the thing you measure.
The resting measurement BEFORE the technique. Without a before-number, an after-number proves nothing.
Safety note (yes, even here): only students in good health, with no breathing problems, should be the participant. That line belongs in every design.
Safety: only participants in good health, with no breathing problems. Anyone can sit out and be the scientist.
Count beats the whole 15 seconds, then × 4.
One full minute of your relaxation technique — nothing else.
| Trial 1 | Trial 2 | Trial 3 | Average | |
|---|---|---|---|---|
| Before (control) | __ | __ | __ | __ |
| After technique | __ | __ | __ | __ |
Record every trial on Worksheet 4 — Lab Data — plus anything you notice (giggling, fidgeting, a door slamming). Observations are data too.
No average, no verdict: a single trial can be luck. Three trials and an average is what makes your conclusion trustworthy tomorrow.
If it did not work — you still did science. Scientists change the hypothesis, fix the procedure, or ask a new question. A "no" answered honestly beats a "yes" you cannot trust.
Clinical trials test new medicines and treatments on real people. In a controlled trial, one group gets the treatment and the control group does not — exactly like your baseline, but with human lives attached.
There is no easy answer. Trials are designed to protect participants AND to produce evidence you can trust. Argue both sides before you settle, detective.
Meet Haley Brouwer, a research scientist who develops medical devices. Living with diabetes gave her a passion for building devices that help others. Off the clock: piano, kayaking, and reading.
Experimental design is the shared language of every research job — medicine, food science, sports science, space.
Claim — answer in one sentence.
Evidence — use your own experiment: a number, a control, a trial.
Reasoning — connect the evidence to the claim.
You asked a testable question, predicted, controlled, measured, and concluded from evidence. That is the whole toolkit — and you will use it for the rest of this unit.
Next up: Activity 1.3 — Disease Agents, where the microscopic suspects finally show themselves.
Every academic word in Activity 1.1. Tap one for the full card.
Click any slide to jump there.